Pneumatic conveyance system for particulate material

ABSTRACT

A pneumatic conveyance system for particulate material, particularly for reclaiming chemically bonded moulding sand from foundry moulds. The material is broken down and/or scrubbed during conveyance through the system which has a surface portion formed with peaks and depressions positioned in the path of flow of the material which break down and/or scrub the material as it strikes said surface portion.

United States Patent Edwards July 29, 1975 [54] PNEUMATIC CONVEYANCESYSTEM FOR 2,362,351 11/1944 Burmeister et a1. 241/5 PARTICULATEMATERIAL 2,818,358 12/1957 Brownell et a1 241/40 X 2,853,241 9/1958Gindoff ct a1 241/40 X [75] Inventor: Albert Edwards, Peterborough, I

England Primary Examiner-Granville Y. Custer, Jr. [73] Asslgnee'322;132:3 gg sgzfi Attorney, Agent, or Firm-Larson, Taylor & Hinds [22]Filed: Mar. 25, 1974 [211 Appl. No.: 454,707 [57] ABSTRACT A pneumaticconveyance system for particulate mate- F A t P t D [30] orelgn y atarial, particularly for reclaiming chemically bonded Mar. 28, UnitedKingdom moulding Sand from foundry moulds- The material is broken downand/or scrubbed during conveyance [52] 241/5; 241/275 5 5; through thesystem which has a surface portion [51] hit. I; g /1 formed with peaksand depressions positioned in the [58] held of Search 41/5 2 0 path offlow of the material which break down and/or References Cited scrub thematerial as it strikes said surface portion.

UNITED STATES PATENTS 7 Claims, 3 Drawing Figures 1,393,287 10/1921Hunter 241/40 X SHEET PATENTED JUL29 I975 PATENTEB JUL 2 9 I975 SHEETPNEUMATIC CONVEYANCE SYSTEM FOR PARTICULATE MATERIAL The presentinvention relates to a pneumatic conveyance system for particulatematerial and more particularly to a sand reclamation plant forreclaiming chemically bonded moulding sand from used foundry moulds orcores.

In known sand reclamation plants, sand agglomerates comprising sandparticles coated with binder are crushed and thereafter graded byvarious classifying units, any particles over a predetermined size beingrecirculated for further classification. A certain amount of scrubbingand further crushing of sand particles also occurs during conveyancethrough the plant after initial processing in a crusher device forexample.

The pneumatic conveyance system of the present invention furtherincreases breaking down and/or scrubbing of the sand agglomerates afterinitial crushing in a crusher device. However, it must be understoodthat the pneumatic conveyance system of the present invention can beused whenever particulate material of any nature is to be broken downand/or scrubbed.

Accordingly therefore, the present invention provides a pneumaticconveyance apparatus for particulate material including a conduit forreceiving and conveying agglomerated particulate material, an internalsurface portion being formed within the conduit and having peaks anddepressions positioned in a path of flow of the material which, in use,break down and/or scrub said material striking the surface portionduring conveyance of the material in the conduit.

Preferably, the surface portion forms at least a part of a conveyancewall of the system. The system may have a cyclone separator wherein thesurface portion forms at least a part of an internal wall of the cycloneseparator.

The surface portion may be arranged to deflect material through more orless than 90 and the system may be a sand reclamation plant.

The invention will now be further described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic side view of a sand reclamation plant,

FIG. 2 illustrates in side section a portion of the plant of FIG. 1, and

FIG. 3 illustrates the portion of the plant illustrated in FIG. 2 takenalong line AA in FIG. 2.

With reference to FIG. 1 the plant comprises a feed input foragglomerates of material from used foundry cores or molds, theagglomerates being from sand grain size up to lumps of approximately 4inches cube. The feed input 10 has a screen 11 for separating theagglomerates, the finer particles passing through the screen 11 to avibratory screen 12 for further separation whilst the larger lumps andparticles pass along to an adjacent jaw crusher 13 to be broken down andlikewise fed to the vibratory screen 12. Hard substances, as forexample, tramp metal is allowed to pass between the jaw crusher 13through the provision of a yieldable jaw when the pressure between thejaws exceeds a predetermined value. The hard material is conveyed alongthe top of the vibratory screen 12 and discharged into a suitablecontainer 14. Suction conduit means 15, the inlet end of which ispositioned through an opening in the screen 12, enables the screenedparticles to be sucked up to a cyclone separator 16 via the suctionconduit means 15.

Referring more particularly now to FIG. 2, the suction conduit means 15has a sharp right angled turn leading to the cyclone separator 16 thepurpose of which will be later described. Disposed at the rightangledturn in the conduit means 15 is a surface in the form of a corrugated orribbed plate 17 manufactured from a very hard material e.g., white iron.A similar corrugated or ribbed surface 18 is positioned with a trailingedge adjacent the inlet of the cyclone separator 16 and a leading edgepositioned on the horizontal centre-line looking in plan view of theseparator. At the top and centrally disposed in the separator 16 is aT-shaped conduit 19 having a slidably mounted tubular member 20 shown inits uppermost position. At the bottom of the separator, see FIG. 1, is athick rubber valve 21 which is self-opening depending on the quantity ofsand in the lower part of the separator 16. The sand particles aredischarged through valve 21 on to a further vibratory screen 22 wherebythe grannular size particles pass through the screen to discharge outlet23 and any larger size particles pass along the top of the screen andfall through a gap (not shown) therein into space 24 and from here thesand particles are drawn up the conduit 15 again for further processing.

A suction fan 25, which exhausts to atmosphere, is provided andassociated with an air filter unit 26 and dust hopper 27, the latterhaving a conduit 28 which connects with T-shaped conduit 19 associatedwith separator 16.

In operation, the screened sand which constitutes the sand beingreclaimed is pneumatically conveyed upwards in the conduit means 15 at avelocity, for example, of approximately 6,000 ft./Min. At theright-angled turn in the conduit 15 a breaking down of the sandagglomerate into separate grains occurs together with a scrubbing actionwhich removes any used binder from the sand grains by the high speedimpact of the material on the corrugated or ribbed plate 17. Furtherbreaking down and scrubbing takes place on entry into the cycloneseparator 16 upon impact of the material on the ribbed member 18.Adjustment of the tubular member 20, which in FIG. 2 is shown in theraised position, enables the plant operator to classify the granularsize particles from the dust and any foreign matter, for example, resinparticles. With tlhe tubular member 20 in the raised position thetendency would be for a substantial amount of the granular sizeparticles together with dust and foreign matter to be drawn through theT- shaped conduit 19 and into the dust hopper 27. It will, of course, beappreciated that in lowering the tubular member 20 in the direction ofthe conical portion of the cyclone separator 16 wherein the air velocityis decreasing, the pneumatically conveyed material can be classifiedi.e., the granular size particles fall out of suspension whilst thefines are drawn into the dust hop per 27 and the dust is filtered off.The granular size particles discharged from outlet 23 via screen 22,valve 21 and cyclone separator 16 may be conveyed to a storage containerfor re-use in the manufacture of foundry cores or moulds wherein thesand is chemically bonded as for example in the Furan Process.

The pneumatic conveying system described above with reference to FIGS. 1and 2 relates to a sand reclamation plant. However, the system can beused for the treatment of at least most particulate materials.

I claim:

1. A method of treating particulate material, said method comprisingusing suction means to receive and convey agglomerated particulatematerial,

breaking down, in a separator means, the particulate material conveyedfrom the suction means, screening the particulate material after thelatter has been broken down, and

returning the non-screen material to the suction means, said receivingand conveying step including disposing an internal surface member,having peaks and depressions formed thereon, within the suction means,in the path of flow of the particulate material, so that the particulatematerial is broken down and scrubbed by collision with the internalsurface member during conveyance through said suction means.

2. Apparatus for treating particulate material comprising suction meansfor receiving and conveying agglomerated particulate material, separatormeans for receiving and breaking down the particulate material conveyedthereto from said suction means, screening means for receiving andscreening broken down particulate material conveyed thereto from saidseparator means and for returning non-screened material to said suctionmeans, said suction means being provided with an internal surface memberhaving peaks and depressions formed thereon and disposed within the pathof flow of particulate material whereby the particulate material isbroken down and scrubbed by collision with the internal surface memberduring conveyance through said suction means.

3. Apparatus as claimed in claim 2, wherein said separator means isprovided with a surface portion having peaks and depressions formed onat least a part of an internal wall thereof and a suction fanoperatively associated with said separator means.

4. The pneumatic conveyance apparatus of claim 2 wherein said suctionmeans comprises a curved conduit portion.

5. The pneumatic conveyance apparatus of claim 4, wherein the internalsurface member forms at least a part of the conveyance wall of theconduit portion.

6'. The pneumatic conveyance apparatus of claim 2, wherein said internalsurface member comprises a ribbed plate forming said peaks anddepressions.

7. The pneumatic conveyance apparatus of claim 6,

wherein said ribbed plate is formed of white iron.

1. A METHOD OF TREATING PARTICULATE MATERIAL SAID METHOD WHEREIN A BELLFORMED ON AN END OF THE FIRST LENGTH IS ENGAGED UNSING SUCTION MEANS TORECEIVE AND CONVEY AGGLOMERATED PARTICULATE MATERIAL, BREAKING DOWN IN ASEPARATOR MEANS THE PARTICULATE MATERIAL CONVEYED FROM THE SUCTIONMEANS, SCREENING THE PARTICULATE MATERIAL AFTER THE LATTER HAS BEENBROKEN DOWN AND RETURNING THE NON-SCREEN MATERIAL TO THE SUCTION MEANSSAID RECEIVING AND CONVEYING STEP INCLUDING DISPOSING AN INTERNALSURFACE MEMBER HAVING PEAKS AND DEPRESSIONS FORMED THEREON WITHIN THESUCTION MEANS IN THE PATH OF FLOW OF THE PARTICULATE MATERIAL SO THATTHE PARTICULATE MATERIAL IS BROKEN DOWN AND SCRUBBED BY COLLISION WITHTHE INTERNAL SURFACE MEMBER DURING CONVEYANCE THROUGH SAID SUCTIONMEANS.
 2. Apparatus for treating particulate material comprising suctionmeans for receiving and conveying agglomerated particulate material,separator means for receiving and breaking down the particulate materialconveyed thereto from said suction means, screening means for receivingand screening broken down particulate material conveyed thereto fromsaid separator means and for returning non-screened material to saidsuction means, said suction means being provided with an internalsurface member having peaks and depressions formed thereon and disposedwithin the path of flow of particulate material whereby the particulatematerial is broken down and scrubbed by collision with the internalsurface member during conveyance through said suction means. 3.Apparatus as claimed in claim 2, wherein said separator means isprovided with a surface portion having peaks and depressions formed onat least a part of an internal wall thereof and a suction fanoperatively associated with said separator means.
 4. The pneumaticconveyance apparatus of claim 2 wherein said suction means comprises acurved conduit portion.
 5. The pneumatic conveyance apparatus of claim4, wherein the internal surface member forms at least a part of theconveyance wall of the conduit portion.
 6. The pneumatic conveyanceapparatus of claim 2, wherein said internal surface member comprises aribbed plate forming said peaks and depressions.
 7. The pneumaticconveyance apparatus of claim 6, wherein said ribbed plate is formed ofwhite iron.